BibTex format
@article{Rham:2019,
author = {Rham, CD and Tolley, AJ},
title = {The speed of gravity},
url = {http://arxiv.org/abs/1909.00881v2},
year = {2019}
}
Publications
Citation
RIS format (EndNote, RefMan)
TY - JOUR
AB - Within the standard effective field theory of General Relativity, we showthat the speed of gravitational waves deviates, ever so slightly, fromluminality on cosmological and other spontaneously Lorentz-breakingbackgrounds. This effect results from loop contributions from massive fields ofany spin, including Standard Model fields, or from tree level effects frommassive higher spins $s \ge 2$. We show that for the choice of interactionsigns implied by S-matrix and spectral density positivity bounds suggested byanalyticity and causality, the speed of gravitational waves is in generalsuperluminal at low-energies on NEC preserving backgrounds, meaninggravitational waves travel faster than allowed by the metric to which photonsand Standard Model fields are minimally coupled. We show that departure of thespeed from unity increases in the IR and argue that the speed inevitablyreturns to luminal at high energies as required by Lorentz invariance.Performing a special tuning of the EFT so that renormalization sensitivecurvature-squared terms are set to zero, we find that finite loop correctionsfrom Standard Model fields still lead to an epoch dependent modification of thespeed of gravitational waves which is determined by the precise field contentof the lightest particles with masses larger than the Hubble parameter today.Depending on interpretation, such considerations could potentially havefar-reaching implications on light scalar models, such as axionic or fuzzy colddark matter.
AU - Rham,CD
AU - Tolley,AJ
PY - 2019///
TI - The speed of gravity
UR - http://arxiv.org/abs/1909.00881v2
UR - http://hdl.handle.net/10044/1/77446
ER -